embedded systems 1
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Embedded System Design and Development
Introduction to Embedded System
Embedded SystemsEmbedded Systems
Embedded - Fix firmly in a surrounding areas
System - Set of connected things
Embedded systemsEmbedded systems
Embedded System is a combination of hardware and software used to achieve a single specific task.
Embedded systems are computer systems that monitor, respond to, or control an external environment.
Environment connected to systems through sensors , actuators and other I/O interfaces.
Embedded system must meet timing & other constraints imposed on it by environment
The EssenceAn embedded system is a microcontroller-based, software driven, reliable, real-time control system, autonomous, or human or network interactive, operating on diverse physical variables and in diverse environments, and sold into a competitive and cost conscious market.
What an Embedded system is not ?What an Embedded system is not ?
Not a computer system that is used primarily for processing
Not a software system on PC or Unix
Not a traditional business or scientific application
ENVIRONMENT CONNECTEDENVIRONMENT CONNECTED
Applications Applications
CharacteristicsCharacteristics In-built Intelligence. Immediate control of hardware. Uses dedicated software. Performs a specific function. Their work is subject to deadlines. Respond to external events. Timeliness, Robustness/Safety Processing power and Memory limitations Program is stored in nonvolatile memory such that it can be
executed on power up. Mostly interactive with I/O devices in the real world. Cope with all unusual conditions without human intervention
CategoriesCategories
EMBEDDED SYSTEMS
MICROCONTROLLERS DSP ASIC
ClassificationClassification
Real Time Systems
RTS is one which has to respond to events within a specified deadline
– A right answer after the dead line is a wrong answer RTS are classified in to three categories
Hard Real Time Systems Soft Real Time System Firm Real Time System
Hard Real Time Systems "Hard" real-time systems have very narrow response time Example: Nuclear power system , Cardiac pacemaker.
Soft Real Time System "Soft" real-time systems have reduced constrains on
"lateness" but still must operate very quickly and repeatable. Example: Railway reservation system – takes a few extra
seconds the data remains valid.
Firm Real Time System Firm deadliness are a combination of both hard and soft
timeliness requirements.
FailureFailure Safety Critical The failure of the system may lead to disastrous/ damage
to safety of the system/environment. Example: Control Systems in Nuclear applications, Flight Control Systems, Life Monitoring Systems, etc.
Mission Critical The failure may lead to non-accomplishment of the mission
and the time spends will be wasted .The system had to run again to complete the missions. Example: Test Equipment
Non-critical The failure does not have much impact. Example: Washing
Machines, etc.
How are embedded systems different How are embedded systems different than traditional software ?than traditional software ?
Responding to sensors (was this button pushed?)
Turning on actuators ( Turn on power to the boiler)
Real - Time (respond to temperature change within 3 seconds)
Differences between ES and traditional Differences between ES and traditional software developmentsoftware development
Not dealing with only sequential code
Routine can stop at completion or in response to an external event
Many parts of system might be running concurrently
Safety- critical component of many systems
Embedded System RequirementsEmbedded System Requirements
Types of requirements imposed by embedded applications:
R1 Functional Requirements
R2 Temporal Requirements
R3 Dependability requirements
R1 Functional RequirementsR1 Functional Requirements
Data Collection– Sensor requirements– Signal conditioning– Alarm monitoring
Direct Digital Control– Actuators
Man-Machine Interaction– informs the operator of the current state of the controlled
object– Assists the operator in controlling the system
R2 Temporal RequirementsR2 Temporal Requirements
Tasks may have deadlinesMinimal latency jitterMinimal error detection latencyTiming requirements due to tight software
control loopsHuman interface requirements
R3 Dependability RequirementsR3 Dependability Requirements
ReliabilitySafetyMaintainabilityAvailabilitySecurity
Major componentsMajor components
Data Acquisition and processingCommunicationSystem logic and control algorithmInterfaceAuxiliary units
– Display– Storage– Monitoring and protection– test and diagnosis
Design and DevelopmentDesign and Development
Cost
Processing power
Memory size and Cost
Number of units
Expected life time
Throughput
Response Time
Testability/Debugging
Program Installation
Languages usedLanguages used
C
C++ Java
Linux
Ada Assembly
Embedded development toolsEmbedded development tools
Host machine
Target machine
PROM Programmers
Simulators
In Circuit Emulator
In Circuit Debugger
Millimeters
Cathode Ray Oscilloscope
Logic analyzers